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Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women

Wilkinson, Daniel J.; Bukhari, Syed S.I.; Phillips, Bethan E.; Limb, Marie C.; Cegielski, Jessica; Brook, Matthew S.; Rankin, Debbie; Mitchell, William K.; Kobayashi, Hisamine; Lund, Jonathan; Williams, John P.; Greenhaff, Paul L.; Smith, Kenneth; Atherton, Philip J.

Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women Thumbnail


Authors

Syed S.I. Bukhari

BETH PHILLIPS beth.phillips@nottingham.ac.uk
Professor of Translational Physiology

Marie C. Limb

Jessica Cegielski

Debbie Rankin

William K. Mitchell

Hisamine Kobayashi

JONATHAN LUND JON.LUND@NOTTINGHAM.AC.UK
Clinical Associate Professor

JOHN WILLIAMS john.williams7@nottingham.ac.uk
Clinical Associate Professor

PAUL GREENHAFF PAUL.GREENHAFF@NOTTINGHAM.AC.UK
Professor of Muscle Metabolism

KENNETH SMITH KEN.SMITH@NOTTINGHAM.AC.UK
Professor of Metabolic Mass Spectrometry

PHILIP ATHERTON philip.atherton@nottingham.ac.uk
Professor of Clinical, metabolic & Molecular Physiology



Abstract

© 2017 The Authors Background & aims: Impaired anabolic responses to nutrition and exercise contribute to loss of skeletal muscle mass with ageing (sarcopenia). Here, we tested responses of muscle protein synthesis (MPS), in the under represented group of older women, to leucine-enriched essential amino acids (EAA) in comparison to a large bolus of whey protein (WP). Methods: Twenty-four older women (65 ± 1 y) received (N = 8/group) 1.5 g leucine-enriched EAA supplements (LEAA_1.5), 6 g LEAA (LEAA_6) in comparison to 40 g WP. A primed constant I.V infusion of 13 C 6 -phenylalanine was used to determine MPS at baseline and in response to feeding (FED) and feeding-plus-exercise (FED-EX; 6 × 8 unilateral leg extensions; 75%1-RM). We quantified plasma insulin/AA concentrations, leg femoral blood flow (LBF)/muscle microvascular blood flow (MBF), and anabolic signalling via immunoblotting. Results: Plasma insulineamia and EAAemia were greater and more prolonged with WP than LEAA, although LEAA_6 peaked at similar levels to WP. Neither LEAA or WP modified LBF or MBF. FED increased MPS similarly in the LEAA_1.5, LEAA_6 and WP (P < 0.05) groups over 0–2 h, with MPS significantly higher than basal in the LEAA_6 and WP groups only over 0–4 h. However, FED-EX increased MPS similarly across all the groups from 0 to 4 h (P < 0.05). Only p-p70S6K1 increased with WP at 2 h in FED (P < 0.05), and at 2/4 h in FED-EX (P < 0.05). Conclusions: In conclusion, LEAA_1.5, despite only providing 0.6 g of leucine, robustly (perhaps maximally) stimulated MPS, with negligible trophic advantage of greater doses of LEAA or even to 40 g WP. Highlighting that composition of EAA, in particular the presence of leucine rather than amount is most crucial for anabolism.

Citation

Wilkinson, D. J., Bukhari, S. S., Phillips, B. E., Limb, M. C., Cegielski, J., Brook, M. S., …Atherton, P. J. (2018). Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women. Clinical Nutrition, 37(6), 2011-2021. https://doi.org/10.1016/j.clnu.2017.09.008

Journal Article Type Article
Acceptance Date Sep 19, 2017
Online Publication Date Sep 23, 2017
Publication Date Dec 1, 2018
Deposit Date Nov 7, 2017
Publicly Available Date Nov 7, 2017
Journal Clinical Nutrition
Print ISSN 0261-5614
Electronic ISSN 1532-1983
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 37
Issue 6
Pages 2011-2021
DOI https://doi.org/10.1016/j.clnu.2017.09.008
Keywords Muscle protein synthesis; Leucine; Ageing; Low dose amino acid supplementation; Exercise; Human metabolism
Public URL https://nottingham-repository.worktribe.com/output/883934
Publisher URL https://www.sciencedirect.com/science/article/pii/S0261561417313407
Additional Information This article is maintained by: Elsevier; Article Title: Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women; Journal Title: Clinical Nutrition; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.clnu.2017.09.008; Content Type: article; Copyright: © 2017 The Authors. Published by Elsevier Ltd.
Contract Date Nov 7, 2017

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